Conventional transfer apparatus have a transfer arm, as defined by an object-supporting rod connected with a link mechanism, which horizontally rotates about a support member to support the transfer arm and which moves up and down, or, in addition, moves back and forth diametrically about said support member. The transfer arm cannot rotate across the axis of the support member or in a vertical plane that includes said axis. When transferring an object from the left side of the support member to the right side thereof, the transfer arm must be rotated about the support member. Therefore, the transfer from the left to the right becomes impossible if there is any obstacle in the way in which the object rotates.
Further, it is desired that the unloaded transfer arm be kept in a substantially balanced condition wherever it moves. With conventional transfer arms, however, it has been difficult to stabilize the balanced moments thereof in accordance with changes in the arms' position because they have only one balance weight.